Abstract: In an electro-elution apparatus for operation in an electrophoresis chamber and for the electro-elution of biological macromolecules from sections of electrophoresis gel, the macromolecules which are to be eluted are not temporarily adsorbed in a gel, but can be collected between two polymer membranes in a trap and pipetted out of the latter. The membrane, which is the first or inner membrane in the direction of migration of the macromolecules, is here permeable to the macromolecules under the action of the electric field, while the membrane, which is the second membrane in the direction of migration, namely the outer membrane of the electro-elution apparatus, is impermeable to the macromolecules under the same conditions. After the electric field has been switched off, both membranes are at least substantially impermeable to any mass transfer.